Some applications require something other than a self-sealing screw or bolt. Often, the Seelnut will do the job. If a piece of hardware (for example, a hinge or a mounting bracket) or other item is being fastened to the outside of an enclosure, something is needed on the inside of the enclosure to seal the assembly. Seelnuts are available in plated steel, stainless steel, plated brass and other materials, and will properly seal the enclosure. The sealing material is normally silicone rubber, with other optional materials available.